Recovery of ammonia



.une 5, i923.

L. E. DOTY RECOVERY OF AMMONIA Filed'Aug. 19.

Patented June 5, 11923..

MINUTE@ STATES LEMAN E DOTY, 03E EJYBIA, OSIEU.

Application filed August it, 1921. Serial to. 498,649.

T o all wlwm t may concer/n:

Be it known that l, LEMAN E. Do'rr, a citizen of the United States, andresident of Elyria., in the county of Lorain and State of Ohio, haveinvented certain new and useful Improvements in the Recovery of Ammonia,of Which the following 1s a specication.

This invention relates to the production of concentrated ammonia liquor`from byproduct coke plants, and more particularly relates to an improvedprocess for the .production of such li uor which will materiallyincrease the yiel of such liquor, without 16 the addition of newequipment.

HeretoforeA the amount of ammonia dropped out of the gases in the formof ammonia liquor has been about 25 per cent of the total ammoniarecovered. Generally it is desirable to keep the total amount of ammoniadropped as li uor at as low a percentage as possible. owever, due to thevarious conditions it is sometimes desirable to increase the percentageof ammonia 2e dropped out as liquor, and to recover it as a concentratedliquor, and it is to this end that my invention pertains.

According to the process of this invention, the yield. of ammonia in theform of t3@ liquor may be increased to about 40 per cent of the totalyield.

Essentially the present process consists of eliminating the condensatescoming down in the cooling process from the recirculat- Se ing orflushing liquor, and distilling these condensates into a concentratedliquor as they condense, and addingy fresh water or other fluid to theflushing mixture to replace the eliminated condensates. The fresh c@water or other fluid is preferably added to the gas by spraying it intothe collecting mains, and readily absorbs additional ammonia from thegas so that about 40 per cent of the total ammonia recovered may @a berecovered as concentrated ammonia" liquor.

The rocess will now be described in de tail, re erringto the drawingwhich shows diagrammatically the flow path of the gas,

so tar and ammonia liquor.

The distillation gas rising from the coking chambers 2 passes throughascension pipes 43 to collecting main 4, which in the usual practice,

ter-y or ovens. The gas is drawn from the collects the gas from abatcollectin main 4c through suction' mains 5 and 6 W ich are separatedby a tar trap 7 to remove any condensed tar which may collect in themains 5 and 6. The tar from the trap flows through a return pipe -8 totar flushing return pipe 9 which connects the collecting main 4c with atar flushing and hot drain tank 10. i

From the suction main 6 the gas is drawn through a primary cooler 11which is of Well known desivn and consists primarily of an outer sheldivided into sections by transverse walls 12 whichV alternately terminate short of the top and bottom walls, thereby causing` the gas toflow alternately up and down through said cooler in a staggered path.Each chamber is provided with water circulation pipes to cool the gas,the water entering through inlet pipe 14 and exiting through outlet pipe13.

During the passage throu h the primary cooler, the gas is so cooled t atmost of the tar and water vapor contained therein are condensed. Fromthe primary cooler 11 the gas is drawn through a suction main 16 to theexhauster 17 which forwards the gas through a main 18 to a tar extractor19 from which the gas flows through main 20 to a re-heater 21 where thelast traces of tar are removed. From thel re-heater 21, the tar freedand super-heated gas flows through a main 22 to the saturatpr 23, wherethe ammonia left in the gas combines with sulfuric acid to form sulfateof ammonia. The condensates from the primary coolerlow into pipe 24which yis connected to a pipe 25 leading to chamber 26 of the tarflushing and hot drain tank. The exhauster 17 is provided with acondensate outlet conduit or pipe 27 which is connected to pipe 25, andthe tar extractor 19 and re-V heater 21 are provided with condensateoutlet conduits or pipes 28 and 29, respectively, which connect with thepipe 27 Jfrom the exhauster. lt will thus be seen that all thecondensates are conducted to the chamber 26 of the tank 10.

From chamber 26 of the tar flushing and hot drain tank 10 thecondensates are pumped by pump 30 through pipe line 3l into a separatingtank 32, where the tar and ammonia liquor are allowed to separate byspeciiic gravity. The ammonia liquor is pumped through pipe 33 by pump34 to the ammonia' still '35 where the ammonia va- Y Bil@ l ammonialiquor.

pors are driven off. These vapors are then treated in a condensing plant(not shown) and converted 4into a concentrated liquor.

The tar from the separating tank 32 flows through pipes 36 and 43 into acompartment 37 of the tar flushing tank 10, which compartment containsthe tar for flushing.

The flushingtar from compartment 3T is continually circulated by pump 33and pipe line 39 through the collecting mains 4 to prevent theaccumulation of pitch. and said flushing tar is returned from main 4through the pipe line 9.

A pump 40 and pipe line 41 is connected to the compartment 37 of the tarflushing and hot drain' tank to force the taras it accumulates, fromsaid compartment into thevtar storage tank 42 from whence it inay bedispensed, While anyammonia liquor floating on top ofthe tar flows backto compartment 37 of tank 10 through pipe 43.

Fresh Water or other absorbing fluid is added to the gas in the gascollecting main in the form of a line spray, through pipe 44.

It will readily be seen that instead of returning the ammoniacondensates to the flushing mixture, they are taken out of the system asthey condense, and distilled into a higher concentrate. The liquor thusremoved is replaced by fresh Water or other absorbing fluid, which isreadily vaporized by the hot gas, and absorbs additional ammonia. Thisadded fluid then condenses as .It has been found that in carrying outthis process in actual practice, the ammonia recovered as concentratedliquor is increased fromthe usual 25 per cent of the total ammoniarecovered, to 40 per cent, While, of course, the yield in the form ofsulfate is correspondingly reduced.

While I have shown a specific. form of apparatus for carrying out myinvention and have described specific detail steps of my process, l donot Wish to be limited thereto, since various apparatus may be used tocarry out my process, and slight modifications in the steps oftheprocess may be made Without departingr from the spirit of myinvention as defined in the appended claims.

I claim 1. The improved process for recovering ammonia liquor fromby-product coke oven gas, which consists in cooling the gases to formcondensates of tar and ammonia liquor, collecting said condensates,separating the tar andammonia liquor, removing the ammonia liquor fromthe circulating system, recirculating the Atar through 'the' gas mains,and adding fluid to said gases prior to cooling them to absorb theainmonia in said gasses and form ammonia liquor.

2. The improvedlprocess for recovering ammonia liquor from b'y-productcoke oven gas. which consists in cooling the gasses to form condensatesof Vtar and ammonia liquor, collecting said condensates, separating thetar and ammonia liquor, removing the ammonia liquor from the circulatingsystem, recirculating the tar through the gas mains, and spraying freshwater into said gases prior to cooling them to absorb the ammonia insaid gas and form ammonia liquor.

3. The improved process for recovering concentrated ammonia liquor fromb product coke oven gas, ywhich consists 1n collecting said gas from aplurality of ovens in a collecting main, cooling said gas to formcondensates composed of tar and arnmonia liquor. collecting saidcondensates,

separating said. tar and ammonia liquor,"

passing 'said ammonia liquor to a suitable still, recirculating saidtal' through said collecting main, spraying fresh water into said.collecting main to absorb the ammonia in said gas and form ammonialiquor, and distilling the ammonia liquor in said still to form aconcentrated liquor.

4. The improved process for recovering concentrated ammonia liquor frombyproduct coke oven gas, Which consists in 'collecting said gas from aplurality of ovens in a collecting main, cooling said gas to formcondensates composed of tar and. ammonia liquor, separating said tar andammonia liquor, passing said ammonia liquor to a suitable still,recirculating said tar through said collecting main, and spraying freshwater intosaidcollecting main to absorb the ammonia in said gas and formammonia liquor.

5. The improved process for recovering concentrated ammonia liquor frombyproduct coke oven gas, which includes as steps thereoffspraying freshwater into the gas to absorb the ammonia content thereof and formammonia liquor when the gas is cooled, cooling the gas to form acondensate of tar and ammonia liquor, removingl the ammonia liquor fromthe system and distilli'ng it to form a concentrated liquor, andrecirculating said `separated tar. i

In testimony whereof, I have hereunto set my hand. 4

LEMAN E. rr.

